A reaction force output device which applies a reaction force corresponding to a depressed state of an accelerator pedal to an accelerator pedal to suppress application of more depression of the accelerator pedal than necessary when a vehicle starts or runs is known as one of power transmission devices (for example, referring to the following Patent Literature 1).
In an accelerator pedal apparatus disclosed in Patent Literature 1, a return spring for returning an accelerator pedal to an initial position, a motor for generating a reaction force and a transmission lever for transmitting rotation of the motor to the accelerator pedal are built in a housing which rotatably supports a base end of the accelerator pedal. In the accelerator pedal apparatus, the motor is controlled by a driving force corresponding to a depressed state of an accelerator pedal, and the driving force is applied to the accelerator pedal through the transmission lever.